Carbon Fibre Filament Guide:
PLA-CF, PETG-CF & PA-CF on Bambu Lab

What Is Carbon Fibre Filament, and Why Does It Matter?

Carbon fibre (CF) filaments are standard base materials — typically PLA, PETG, or Nylon/PA — blended with short chopped carbon fibers, usually 3–5% by weight. The fibers don't reinforce the plastic the way continuous fiber does in aerospace composites; instead, they dramatically increase the stiffness (Young's modulus) of the printed part, reduce thermal expansion, and lower the weight of the filament itself.

The practical result: a PLA-CF bracket flexes far less under load than a plain PLA bracket of the same wall count. A PETG-CF heat shield sits flatter and holds its shape at elevated temperatures. A PA-CF jig for a CNC fixture can replace machined aluminium in light-duty applications. You're not gaining toughness or impact resistance — you're gaining rigidity and dimensional stability.

The flip side is that those same carbon fibers are highly abrasive. They act like fine sandpaper running through the nozzle orifice on every print, and a standard brass nozzle will show measurable wear within a single spool. That's the first — and most important — thing to sort out before you load any CF filament.

Nozzle Requirements: The Non-Negotiable First Step

CF filament is abrasive. The solution is a hard nozzle. Bambu Lab makes this straightforward with its quick-swap hotend system — you don't need to wrestle with a hot nozzle and a wrench; it's a module swap in a few minutes.

For most CF printing, a 0.4mm hardened steel CHF nozzle is the right choice. The standard hardened steel nozzle also works, but the CHF variant's wider flow channel and interior coating maintain higher flow rates more similar to brass, which matters on Bambu Lab's fast-profile presets. For a full breakdown of nozzle materials and sizes, see our Bambu Lab Nozzle Guide.

One nozzle-size caveat: avoid 0.2mm nozzles with CF filament. The short carbon fibers can bridge across the orifice and cause partial clogs, and at 0.2mm you lose most of the speed advantage that makes CF printing worthwhile in the first place. Stick to 0.4mm or larger for CF work.

Once you have the right nozzle, the actual print settings branch depending on which CF base material you're working with.

PLA-CF: The Easy Entry Point

PLA-CF is the most approachable CF variant — it shares PLA's general printing behavior, which means no enclosure required, no heated chamber needed, and no more moisture sensitivity than regular PLA. It's the right first CF filament for anyone who's been printing standard PLA successfully on a Bambu A1 Mini, A1, or P1S.

PLA-CF Settings on Bambu Lab

• Nozzle temperature: 220–235°C. The carbon filler adds thermal mass to the melt, so you'll typically need 10–20°C more than plain PLA. Start at 225°C and go up if you see under-extrusion.
• Bed temperature: 45–60°C. Standard PLA bed temps work fine. A cool-air fan-off first layer improves adhesion on textured PEI.
• Speed: Reduce from your standard PLA profile by 20–30%. CF filament has lower ductility than plain PLA — pushing it too fast on retractions or sharp corners can snap the filament at the drive gear.
• Cooling fan: 70–100% after the first layer. PLA-CF benefits from good cooling to maintain sharp features.
• Retraction: Keep retraction distance short (0.5–1.0mm on Bambu's direct-drive). Longer retractions can break CF filament strands and cause clogs.
• Flow rate: Start at 95% and calibrate. CF filaments often run slightly under the volumetric output of unfilled PLA.

OrcaSlicer ships with a PLA-CF preset for most Bambu Lab printers — it's a solid starting point that already accounts for the temperature and speed adjustments above. Use it as your base and tweak from there.

PETG-CF: More Heat Resistance, Same Abrasion

PETG-CF inherits PETG's useful properties — better heat resistance than PLA, improved chemical resistance, and lower brittleness — while the carbon fibers add the stiffness boost that plain PETG lacks. This makes it a strong choice for parts that see moderate heat or outdoor exposure, like equipment mounts, automotive clips, and enclosure parts.

PETG-CF Settings on Bambu Lab

• Nozzle temperature: 235–255°C. PETG-CF runs hotter than PLA-CF. For Bambu's hardened steel CHF nozzle, 245°C is a reliable starting point.
• Bed temperature: 70–85°C. Standard PETG bed temps. The textured PEI plate gives better first-layer adhesion than the smooth plate for most PETG-CF brands.
• Speed: 40–60% of your standard PETG profile. PETG-CF is even less ductile than plain PETG and can shear at drive gears on aggressive speed or retraction settings.
• Cooling fan: 30–60%. PETG-CF benefits from some cooling but not as aggressively as PLA-CF — too much cooling can reduce layer bonding.
• Enclosure: Not required, but running the Bambu X1C or P1S with the door closed reduces drafts and warping on larger PETG-CF parts.

PA-CF (Nylon Carbon Fibre): High Performance, High Demands

PA-CF — nylon with carbon fibers — is the most capable CF filament and also the most demanding. PA12-CF and PA6-CF printed on an enclosed Bambu printer produce parts with genuinely impressive stiffness-to-weight ratios, very good heat resistance, and inherent chemical resistance. This is the category where 3D-printed parts start replacing machined aluminium in light-duty jigs, fixtures, and structural brackets.

The difficulty is nylon's hygroscopic nature. PA absorbs moisture from the air aggressively — even a few hours at ambient humidity can degrade print quality from excellent to unusable. PA-CF must be printed directly from an actively dried container. The AMS 2 Pro (with its built-in heating) can manage this in many cases; the original AMS and AMS Lite cannot.

PA-CF Settings on Bambu Lab

• Nozzle temperature: 260–280°C. PA-CF runs significantly hotter than PLA-CF or PETG-CF. Start at 270°C for PA12-CF; PA6-CF may need 280°C+.
• Bed temperature: 70–90°C. A PEI plate with glue stick, or an engineering-material plate, is recommended.
• Enclosure: Required. PA shrinks significantly during cooling and will warp without a consistent ambient temperature. The X1C, P1S, and P2S are the right Bambu printers for PA-CF; the open-frame A1 and A1 Mini are not suitable.
• Speed: 30–50% of maximum. PA-CF demands slow, controlled extrusion. Rushing the print typically causes delamination between layers.
• Chamber temperature: If your printer supports active chamber heating (P1S, X1C), use it. Target 40–50°C chamber temperature for PA-CF.
• Drying: Dry PA-CF at 80°C for 8–12 hours before printing. Print directly from a dry box or AMS 2 Pro. If the filament pops or crackles while printing, it's wet — stop, dry, and restart.

CF Filament Types Compared

AMS Compatibility with CF Filaments

Carbon fiber filaments can run through the AMS and AMS Lite without major issues for PLA-CF and PETG-CF, with one thing to keep in mind: the short carbon fibers add slight abrasion to the PTFE tubes inside the AMS hub and feed path over time. This is minor compared to nozzle wear and shouldn't be a concern for typical use, but it's worth inspecting the AMS PTFE tubing if you're running CF filament through it exclusively for hundreds of hours.

The other consideration is purge volume. Multi-material printing with CF filaments produces waste just like any other material. The purge volume needed to clear CF from the nozzle before switching to a plain filament is the same as clearing any filled material — standard Bambu Lab AMS purge settings work fine.

For PA-CF specifically: the AMS Lite lacks active heating and cannot keep Nylon dry during a print. The AMS 2 Pro, with its active humidity and temperature control, is the unit that makes PA-CF in a multi-spool setup practical. If you're on an A1 or A1 Mini with AMS Lite, limit CF use to PLA-CF and PETG-CF and keep PA-CF in a separate dry box fed directly to the extruder.

For a full comparison of the AMS options, see our AMS vs AMS Lite guide.

Drying Carbon Fibre Filament

Drying matters for CF filaments — especially the PA-based variants, but even PLA-CF and PETG-CF print noticeably cleaner from a dry spool. Moisture in any CF filament shows up as a rougher surface texture and, at higher temperatures, audible crackling from the nozzle as steam flashes.

• PLA-CF: Dry at 50°C for 4–6 hours before a long print. Not always necessary, but always worthwhile.
• PETG-CF: Dry at 65°C for 6–8 hours. PETG absorbs moisture faster than PLA.
• PA-CF: Dry at 80°C for 8–12 hours minimum. Print from an actively dried container — not from the open air. If you don't have a dryer, don't attempt PA-CF.

For recommended dryer hardware, temperatures, and the oven-vs-dryer comparison for each material, see our How to Dry Filament guide.

Where to Buy CF Filament

Carbon fiber filaments vary significantly in quality. Diameter consistency matters even more than with plain filaments because the filler changes the melt viscosity — a spool with poor diameter tolerance will cause flow-rate swings that show up immediately at the stiffer, less-forgiving CF melt. Stick to brands with published tolerances.